Network Node and Method Therein for Configuring PDCP for a Wireless Device

ABSTRACT

A wireless device is configured for wirelessly communicating with one or more types of Radio Access Networks (RANs) providing control-plane connectivity to one or both of a first type of core network and a second type of core network. The device configures a Packet Data Convergence Protocol (PDCP) at the device, e.g., at least for initial control-plane signaling, in dependence on whether the device is connected, or connecting, to the first type or the second type of core network. In at least one embodiment, the device configures PDCP for the second type of core network as a default choice, when control-plane connectivity to the second core network is available. In an example arrangement, the RAN types are LTE and 5G New Radio (NR), and the core network types are Evolved Packet Core (EPC) and 5G New Generation Core Network (NGCN).

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/800,256 filed 25 Feb. 2020, which is a continuation of U.S.application Ser. No. 15/521,068 filed 21 Apr. 2017, now U.S. Pat. No.10,609,749, which is a U.S. National Phase Application ofPCT/SE2017/050116 filed 8 Feb. 2017, which claims foreign priority toPCT/CN2016/113053 filed 29 Dec. 2016. The entire contents of eachaforementioned application is incorporated herein by reference.

TECHNICAL FIELD

Embodiments herein relate to a network node and a method therein. Inparticular, they relate to configuring a Packet Data ConvergenceProtocol (PDCP) for a wireless device.

BACKGROUND

In a typical wireless communication network, wireless devices, alsoknown as wireless communication devices, mobile stations, stations (STA)and/or user equipments (UE), communicate via a Radio Access Network(RAN) to one or more core networks (CN). The RAN covers a geographicalarea which is divided into service areas or cell areas, which may alsobe referred to as a beam or a beam group, with each service area or cellarea being served by a radio network node such as a radio access nodee.g., a Wi-Fi access point or a radio base station (RBS), which in somenetworks may also be denoted, for example, a NodeB, eNodeB (eNB), or gNBas denoted in 5G. A service area or cell area is a geographical areawhere radio coverage is provided by the radio network node. The radionetwork node communicates over an air interface operating on radiofrequencies with the wireless device within range of the radio networknode.

Specifications for the Evolved Packet System (EPS), also called a FourthGeneration (4G) network, have been completed within the 3rd GenerationPartnership Project (3GPP) and this work continues in the coming 3GPPreleases, for example to specify a Fifth Generation (5G) network alsoreferred to as 5G New Radio (NR). The EPS comprises the EvolvedUniversal Terrestrial Radio Access Network (E-UTRAN), also known as theLong Term Evolution (LTE) radio access network, and the Evolved PacketCore (EPC), also known as System Architecture Evolution (SAE) corenetwork. E-UTRAN/LTE is a variant of a 3GPP radio access network whereinthe radio network nodes are directly connected to the EPC core networkrather than to RNCs used in 3G networks. In general, in E-UTRAN/LTE thefunctions of a 3G RNC are distributed between the radio network nodes,e.g. eNodeBs in LTE, and the core network. As such, the RAN of an EPShas an essentially “flat” architecture comprising radio network nodesconnected directly to one or more core networks. i.e. they are notconnected to RNCs. To compensate for that, the E-UTRAN specificationdefines a direct interface between the radio network nodes, thisinterface being denoted the X2 interface.

Multi-antenna techniques can significantly increase the data rates andreliability of a wireless communication system. The performance is inparticular improved if both the transmitter and the receiver areequipped with multiple antennas, which results in a Multiple-InputMultiple-Output (MIMO) communication channel. Such systems and/orrelated techniques are commonly referred to as MIMO.

In addition to faster peak Internet connection speeds, 5G planning aimsat higher capacity than current 4G, allowing higher number of mobilebroadband users per area unit, and allowing consumption of higher orunlimited data quantities in gigabyte per month and user. This wouldmake it feasible for a large portion of the population to streamhigh-definition media many hours per day with their mobile devices, whenout of reach of Wi-Fi hotspots, 5G research and development also aims atimproved support of machine to machine communication, also known as theInternet of things, aiming at lower cost, lower battery consumption andlower latency than 4G equipment.

5G is currently being standardized in 3GPP while at the same time LTEwill continue evolving which means in a long run, LTE and 5G willcoexist together. Tight interworking between LTE and 5G will providebetter performance for end user and also save the cost for networkoperator. Then there will be several scenarios also referred to asarchitecture or connectivity options according to the standard toconsider how 5G and LTE inter-work.

Currently there is also ongoing standardization of Next Generation CoreNetwork, called NGCN or 5G-CN or similar. The NGCN will supportconnectivity of both 5G radio or NR, and LTE.

Some Definitions

The wording non-standalone as used herein means using LTE as the controlplane anchor for supporting NR 5G as an extra data boost carrier, whicharrangement is also referred to as Dual Connectivity (DC), as comparedto standalone NR 5G, which implies full control plane capability for NR5G.

The wording master node when used herein means the node which is thecontrol plane anchor. The control plane anchor handles initialconnectivity and mobility for the UE such as a wireless device. Themaster node is also responsible for activating the secondary node, alsoreferred to as setup DC. The wording secondary node when used hereinmeans the node that provides user plane connectivity in addition to theuser plane connectivity provided by the master node. The wireless devicein DC is simultaneously connected to both the master and secondary node.

The radio protocol architecture for LTE is separated into a controlplane architecture and a user plane architecture. In the user planebetween the e-Node B and UE, the application creates data packets thatare processed by protocols such as Transmission Control Protocol (TCP),User Datagram Protocol (UDP) and Internet protocol (IP). In the controlplane, the Radio Resource Control (RRC) protocol creates signallingmessages that are exchanged between the eNB and the UE. In both cases,the information is processed by the PDCP, the Radio Link Control (RLC)protocol and the Medium Access Control (MAC) protocol, before beingpassed to the physical layer for transmission.

The relevant options to the discussion in this document comprise thefollowing Non-Standalone scenarios as specified in the standardized in3GPP. The solid lines in the scenarios below represent use plane trafficand the dashed lines in the scenarios below represent control planesignaling connections.

Option 3) is depicted in FIG. 1. In this scenario, a wireless device isusing NR as a secondary node and LTE as master node connected to EPC. Inthis scenario there is no direct user plane between EPC eNB and NR gNBinstead NR traffic is routed via the LTE eNB.

Option 3a) is depicted in FIG. 2. In this scenario, the wireless deviceis using NR as a secondary node and LTE as master node connected to EPC.In this scenario there is a user plane A1 between EPC and the NR gNB. 1Ain FIG. 2 means user plane connection.

Option 4) is depicted in FIG. 3. In this scenario, the wireless deviceis using 5G NR as a master node connected to NGCN. LTE eNB is asecondary node. In this scenario there is no direct user plane betweenNGCN and LTE eNB. LTE user plane is routed via 5G NR node.

Option 4a) is depicted in FIG. 4. Here the wireless device is using 50NR as a master node connected to NGCN. The LTE eNB is a secondary node.In this scenario, a user plane between the NGCN and the LTE eNB isreferred to as 1A like in FIG. 4, which means that the LTE eNB data issent directly to the NGCN.

Option 7) is depicted in FIG. 5. Here, the wireless device is using NRas a secondary node and LTE as master node connected to the EPC. In thisscenario, there is no direct user plane between the EPC eNB and the NRgNB; instead, NR traffic is routed via the LTE eNB.

Option 7a) is depicted in FIG. 6. In this scenario, the wireless deviceis using NR as a secondary node and LTE as a master node connected tothe EPC. In this scenario, there is a user plane 1A between the EPC andthe NR gNB. The annotation 1A like in FIG. 6 means user planeconnection.

From a protocol perspective, the PDCP protocol for NR gNB would bedifferent from that for LTE eNB, similarly, the Non-access stratum (NAS)protocol for 5G NGCN would be different from that for EPC, although theymay be similar.

NAS is a functional layer in the UMTS and LTE wireless telecom protocolstacks between the core network and UE. This layer is used to manage theestablishment of communication sessions and for maintaining continuouscommunications with the user equipment as it moves. The NAS is definedin contrast to the Access Stratum which is responsible for carryinginformation over the wireless portion of the network. A furtherdescription of NAS is that it is a protocol for messages passed betweenthe UEs and core network nodes that are passed transparently through theradio network. Once the UE establishes a radio connection, the UE usesthe radio connection to communicate with the core network nodes tocoordinate service. The distinction is that the Access Stratum is fordialogue explicitly between the UE and the RAN and the NAS is fordialogue between the UE and core network nodes. For LTE, the TechnicalStandard for NAS is 3GPP TS 24.301.

That is, for a UE it can either connect to EPC or connect to 5G NGCN.Its master node may be either LTE eNB or NR gNB, and its secondary nodemay be either LTE eNB or NR gNB.

The problem is that as the UE may either connect to EPC or NGCN, itsmaster node may be either eNB or gNB.

SUMMARY

It is therefore an object of embodiments herein to further improve theperformance of a communications network comprising multiple generationsof communications networks.

According to a first aspect of embodiments herein, the object isachieved by a method performed by a network node for configuring aPacket Data Convergence Protocol, PDCP, for a wireless device in acommunications network. The communications network comprises a firsttype of core network and a second type of core network. The network nodedecides whether the network node is a master node or a secondary nodefor the wireless device.

When the network node is a master node, it configures the PDCP for thewireless device based on which type of core network the wireless deviceconnects to, out of a core network of a first type, and a core networkof a second type.

When the network node is a secondary node, it configures the PDCP forthe wireless device based on any one or more out of:

-   -   Which type of master node the network node connects to, out of a        master node of a first type, and a master node of a second type,        and    -   which type of core network the wireless device connects to, out        of a core network of a first type, and a core network of a        second type.

The first type and the second type relate different generations oftelecommunication networks.

According to a second aspect of embodiments herein, the object isachieved by method performed by a wireless device, for configuring aPacket Data Convergence Protocol, PDCP, for the wireless device in acommunications network. The communications network comprises a firsttype of core network and a second type of core network. The wirelessdevice obtains information about which type of core network the wirelessdevice connects to out of a first type and a second type relating todifferent generations of telecommunication networks. The wireless deviceconfigures the PDCP for the wireless device based on which type of corenetwork the wireless device connects to, out of a core network of afirst type, and a core network of a second type.

According to a third aspect of embodiments herein, the object isachieved by a network node for configuring a Packet Data ConvergenceProtocol, PDCP, for a wireless device in a communications network. Thecommunications network is adapted to comprise a first type of corenetwork and a second type of core network. The network node beingadapted to:

Decide whether the network node is a master node or a secondary node forthe wireless device.

When the network node is a master node, configure the PDCP for thewireless device based on which type of core network the wireless deviceconnects to, out of a core network of a first type, and a core networkof a second type.

When the network node is a secondary node, configure the PDCP for thewireless device based on any one or more out of:—Which type of masternode the network node connects to, out of a master node of a first type,and a master node of a second type, and—which type of core network thewireless device connects to, out of a core network of a first type, anda core network of a second type.

The first type and the second type are adapted to relate to differentgenerations of telecommunication networks.

According to a fourth aspect of embodiments herein, the object isachieved by a wireless device for configuring a Packet Data ConvergenceProtocol, PDCP, for the wireless device in a communications network. Thecommunications network is adapted to comprise a first type of corenetwork and a second type of core network. The wireless device isadapted to:

Obtain information about which type of core network the wireless deviceconnects to out of a first type and a second type adapted to relate todifferent generations of telecommunication networks, and

configure the PDCP for the wireless device based on which type of corenetwork the wireless device connects to, out of a core network of afirst type, and a core network of a second type.

Since the network node configures the PDCP for the wireless device basedon whether it is a master node or a secondary node, which type of corenetwork the wireless device connects to and which type of master nodethe network node connects to, the PDCP can be used by the wirelessdevice in different scenarios. In this way the PDCP is configuredaccording to the actual needs. This results in less signaling and dataoverhead since the PDCP header such as the Protocol Data Unit (PDU)header only need to include the information fields needed for aparticular configuration, which in turn further improves the performanceof a communications network comprising multiple generations ofcommunications networks.

An advantage with embodiments herein is that the same PDCP protocolspecification may be used to support communication with wireless devicesattached to different core networks or master node, and the PDCPprotocol can be optimally configured depending on the differentfunctionalities and features available when connected to different corenetworks or master nodes associated with different generations ofcommunications networks.

BRIEF DESCRIPTION OF THE DRAWINGS

Examples of embodiments herein are described in more detail withreference to attached drawings in which:

FIG. 1 is a schematic block diagram illustrating prior art.

FIG. 2 is a schematic block diagram illustrating prior art.

FIG. 3 is a schematic block diagram illustrating prior art.

FIG. 4 is a schematic block diagram illustrating prior art.

FIG. 5 is a schematic block diagram illustrating prior art.

FIG. 6 is a schematic block diagram illustrating prior art.

FIG. 7 is a schematic block diagram illustrating embodiments of acommunications network.

FIG. 8 is a flowchart depicting embodiments of a method in a networknode.

FIG. 9 is a flowchart depicting embodiments of a method in a wirelessdevice.

FIG. 10 is a flowchart depicting embodiments of a method in a networknode.

FIG. 11 is a schematic block diagram illustrating embodiments of anetwork node.

FIG. 12 is a schematic block diagram illustrating embodiments of awireless device.

DETAILED DESCRIPTION

As part of developing embodiments herein the inventors recognized aproblem which first will be discussed.

The problem is that as a wireless device such as a UE may either connectto EPC or NGCN, its master node may be either eNB or gNB. Which protocolto configure and/or use need be decided. For example, for a NR gNB, oreLTE eNB, if the UE connect with EPC, then it is not necessary for themto configure UE PDCP protocol to support QoS flow ID as this isdetermined or used by NGCN. Another example, for a UE camping in eLTEeNB, if this eLTE eNB connect to NGCN, then it is inappropriate for UEto send EPC version NAS message to NGCN. The wording QoS flow ID whenused herein means an information element transferred in the packetheader over the CN and RAN interface and the radio interface. Over theCN and RAN interface the information element may be sent in a GeneralPacket Radio Services (GPRS) Tunneling Protocol (GTP) header and overthe radio interface it may be sent in the PDCP header. The QoS flow IDis used by the wireless device and the NGCN to indicate which QoS flow agiven packet is related to. This is in turn used to map the packet onthe correct Data Radio Bearer over the radio to ensure correct QoStreatment. The mapping is performed both in the DL in a network nodesuch as an eNB and in the UL in the wireless device. The mapping betweenQoS flow and Data Radio Bearers (DRB) may either be explicitly signaledfrom the RAN node to the wireless device or implicitly indicated by RANnode based on the DL mapping used.

To summarize, both RAN node and UE need to know which version ofprotocol to use in different scenarios.

Embodiments herein provide methods, where each network node such as RANnode may configure PDCP protocol for a wireless device dynamicallyaccording to the core network the wireless device connect to, oraccording to the master node the network node connect to. For thenetwork node being a master node which has signaling with core network,if the core network node is EPC, then QoS flow ID is not necessary to beconfigured. If core network node is NGCN, then QoS flow ID is needed.QoS flow ID should here be seen as an example parameter that may bedifferent depending if the UE is connected to EPC or NGCN. Otherparameters may also be handled in the same way e.g. Header Compressionrelated parameters. Encryption related parameters such as PDCP sequencenumber used as input to encryption algorithm. Integrity protection ofuser data related parameters, or parameters related to in-sequencedelivery, or the size of the PDCP sequence number, which may bedifferent or only be applied if UE is connected to NGCN or if the masternode is an NR gNB. For the network node being a secondary node whichdoes not have signaling with core network, it checks the master node itconnect to. If master node is LTE, then QoS flow ID is not necessary,otherwise. QoS flow ID is needed. This is an advantage since QoS flow IDand other parameters only need to be included in PDCP header whenneeded, including them when they are not needed would add unnecessarysignaling overhead.

Embodiments herein provide methods, wherein the network node is an eLTEeNB and broadcasts in its system Information, such as Master InformationBlock (MIB) or System Information Block (SIB) 1, 2, . . . , that itsupport to connect to NGCN. The system information is today specified in3GPP 36.331 RRC protocol specification. For those wireless devices thatalso support to connect to NGCN, they may send an indication to the eLTEeNB which CN node they want to communicate with. The indication may becarried in RRC protocol or other protocol. In addition to the indicationthey may send a NAS message formatted according to the NAS protocol usedin the respective core network. For example if the wireless device wantsto communicated with the NGCN it will generate a NGCN NAS message andsend this to eLTE eNB so that eLTE eNB can then forward UE NAS messageto NGCN. This is an advantage since it enables the same eLTE eNB toserve both legacy wireless devices connected to EPC and new wirelessdevices connectivity to NGCN. These wireless devices may be multiplexedon the same radio channel or carrier which avoids the need to deploy newcarriers just to serve NGCN users. Deploying new dedicated carriers forNGCN is very expensive for the operator since it needs to obtainlicensed for new frequency bands and need to deploy new radio hardwareon a lot of radio sites.

In some embodiments, whether PDCP protocol need to include QoS flow IDor not depends on whether network node such as the RAN node is a masternode or secondary node, and whether network node such as the RAN nodeconnect to EPC or NGCN, or the RAN node connect to NR gNB or LTE eNB.

Some embodiments herein relate to tight interworking between LTE and 5Gwhich will provide better performance for end user and also save thecost for network operator.

FIG. 7 depicts an example of a wireless communications network 100 inwhich embodiments herein may be implemented. The wireless communicationsnetwork 100 implementing embodiments herein may comprise one or moreRANs and one or more CNs. The wireless communication network 100 may usea number of different technologies, such as Wi-Fi, Long Term Evolution(LTE), LTE-Advanced, 5G, Wideband Code Division Multiple Access (WCDMA),Global System for Mobile communications/enhanced Data rate for GSMEvolution (GSM/EDGE), Worldwide Interoperability for Microwave Access(WiMax), or Ultra Mobile Broadband (UMB), just to mention a few possibleimplementations. Embodiments herein relate to recent technology trendsthat are of particular interest in a 5G context, such as tightinterworking between LTE and 5G. However, embodiments are alsoapplicable in further development of other existing wirelesscommunication systems such as e.g. WLAN, WCDMA and LTE. The wirelesscommunications network 100 may comprise wireless communications networksof a first type and a second type. The first type and the second typerelates different generations of telecommunication networks, such a 4Gwireless communications network and a 5G wireless communicationsnetwork.

The wireless communications network 100 comprises a core network 101 ofthe first type such as e.g. EPC and a core network 102 of the secondtype such as e.g. NGCN.

Network nodes 111, 112 operate in the wireless communication network100. The network nodes 111, 112 providing radio coverage over ageographical area. The network nodes 111, 112 may be a transmission andreception point e.g. a radio access network node such as a WirelessLocal Area Network (WLAN) access point or an Access Point Station (APSTA), an access controller, a base station, e.g. a radio base stationsuch as a NodeB, an evolved Node B (eNB, eNode B), a 5G base stationsuch as a gNB, a base transceiver station, a radio remote unit, anAccess Point Base Station, a base station router, a transmissionarrangement of a radio base station, a stand-alone access point or anyother network unit capable of communicating with a wireless devicewithin the service area served by the network nodes 111, 112 dependinge.g. on the first radio access technology and terminology used. Thenetwork nodes 111, 112 may be referred to as a serving radio networknode and communicates with a wireless device 120 with Downlink (DL)transmissions and Uplink (UL) transmissions from the wireless device120. The network node according to embodiments herein may be any of anetwork node 111 of a first type such as e.g. an eNB of LTE, or anetwork node of a second type such as a gNB of 5G. Therefore the networknode according to embodiments herein is referred to as the network node111, 112. Thus the first type and the second type relate differentgenerations of telecommunication networks. When the network node 111,112 according to embodiments herein is a network node 111 of the firsttype such as e.g. an eNB of LTE, it may operate in a RAN 116 of a firsttype e.g. using LTE. When the network node 111, 112 according toembodiments herein is a network node 112 of the second type such as e.g.a gNB of 5G, it may operate in a RAN 117 of a second type e.g. using 5GNR.

In the wireless communication network 100, radio nodes such as e.g. thewireless device 120 operate. The wireless device 120 may be a UE, mobilestation, a non-access point (non-AP) STA, a STA, a user equipment and/ora wireless terminals, communicate via one or more Access Networks (AN).e.g. RAN, to one or more core networks (CN). It should be understood bythe skilled in the art that “wireless device” is a non-limiting termwhich means any terminal, wireless communication terminal, userequipment, Machine Type Communication (MTC) device. Device to Device(D2D) terminal, or node e.g. smart phone, laptop, mobile phone, sensor,relay, mobile tablets or even a small base station communicating withina cell. The wireless device 120 may support the first type and thesecond type of different generations of telecommunication networks sucha 4G wireless communications network and a 5G wireless communicationsnetwork.

A method for configuring a Packet Data Convergence Protocol. PDCP, for awireless device 120 in a communications network 100, is performed by thenetwork node 111, 112. As an alternative, a Distributed Node (DN) andfunctionality, e.g. comprised in a cloud 130 as shown in FIG. 7, may beused for performing or partly performing the method.

Example embodiments of a method performed by the network node 111, 112for configuring a PDCP for the wireless device 120 in the communicationsnetwork 100, will be described with reference to a flowchart depicted inFIG. 8. As mentioned above the first type and the second type relatedifferent generations of telecommunication networks. The first type oftelecommunication network may relate to 4G. and the second type oftelecommunication network may relate to 5G. The communications network100 comprises a first type of core network 101 and a second type of corenetwork 102.

The method comprises the following actions, which actions may be takenin any suitable order as will be discussed below. Actions that areoptional are presented in dashed boxes in FIG. 8.

Action 801

According to an example scenario, the wireless device 120 is about tocommunicate in the wireless communications network 100. It is served bythe network node 111, 112, i.e. either by the network node 111 or thenetwork node 112. To know how to configure the PDCP for the wirelessdevice 120 in a dynamic way, the network node 111, 112 decides whetherthe network node 111, 112 is a master node or a secondary node for thewireless device 120. This will be a base for deciding how to configurethe PDCP for the wireless device 120 below.

According to an example scenario of embodiments herein, for a RAN nodesuch as the network node 111, 112, the decision of whether aconfiguration of the PDCP protocol need to include parameters or notdepends on the role of this network node 111, 112, whether it is amaster node or a secondary node. The parameters may comprise any one ormore out of: QoS flow ID, Header Compression related parameters,Encryption related parameters such as PDCP sequence number used as inputto encryption algorithm. Integrity protection of user data relatedparameters, or parameters related to in-sequence delivery, or the sizeof the PDCP sequence number.

If the network node 111, 112 is a master node, the network node 111, 112configures PDCP according to which core network the wireless device 120connects to. This is described in Action 803 below. This is sincecertain features of PDCP are only supported or useful for one of thecore networks. If the wireless device 120 connects to first type of corenetwork 101 such as e.g. EPC, then the network node 111, 112 configuresPDCP for the wireless device 120 not to include QoS flow ID. If thewireless device 120 connects to the second type of core network 102 suchas e.g. 5G NGCN, then the network node 111, 112 configures the PDCP forthe wireless device 120 to include QoS flow ID.

If the network node 111, 112 is a secondary node, the network node 111,112 configures PDCP according to which master node the network node 111,112 connects to. This is described in Action 804 below. This is sincecertain features supported by PDCP is only supported or useful if themaster eNB is of a certain type. If the network node 111, 112 connectsto a master node of NR gNB, then it configures PDCP for the wirelessdevice 120 to include QoS flow ID. If it connects to a master node ofLTE eNB, then it configures PDCP for the wireless device 120 to notinclude QoS flow ID.

If the network node 111, 112 is a secondary node, the network node 111,112 may further configure PDCP according to which core network thewireless device 120 connects to. This is also described in Action 804below. This is since certain features of PDCP are only supported oruseful for one of the core networks. If the wireless device 120 connectsto first type of core network 101 such as e.g. EPC, then the networknode 111, 112 configures PDCP for the wireless device 120 not to includeQoS flow ID. If the wireless device 120 connects to the second type ofcore network 102 such as e.g. 5G NGCN, then the network node 111, 112configures the PDCP for the wireless device 120 to include QoS flow ID.

Action 802

In some embodiments, the network node 111, 112 decides which type ofcore network the wireless device 120 connects to, out of the first typeof core network 101, and the second type of core network 102. The firsttype of core network may relate to an EPC core network, and the secondtype of core network relates a 5G core network such as NGCN.

There are different ways for the network node 111, 112 to decide whichtype of core network the wireless device 120 connects to.

One way is to decide it based on statically configured informationobtained from Operations And Management (OAM). E.g. in OAM, it isdesignated which core network node ID that corresponds to EPC, and whichcore node ID corresponds to NGCN, or which IP address corresponds toEPC, which other IP address corresponds to NGCN. The network node 111,112 may then know such information when it decides to contact the corenetwork.

Another way is to decide it based on dynamic information obtained insignaling from the core network. The network node 111, 112 may decidebased on knowing the type of core network via a signaling message fromcore network to the network node 111, 112. The signaling information mayinclude certain protocol or information elements that indicated whichcore network type the network node is communicating with.

In some of these embodiments or in some other embodiments wherein thenetwork node 111, 112 is a secondary node, the network node 111, 112decides which type of master node the network node 111, 112 connects to,out of the first type of master node, and the second type of masternode.

The way for the network node 111, 112 to decide which master node itconnects to may be similar as deciding the type of core network above.

One way is to decide it based on statically configured informationobtained from OAM. That is, in OAM, it is designated which network nodeID such as RAN node ID that corresponds to an LTE eNB, and which networknode ID that corresponds to the NR gNB, or which IP address correspondsto a node of NR gNB, which node ID or IP address corresponds to a nodeof LTE eNB.

Another way is to decide it based on dynamic information from signalingfrom the master node such as a RAN master node. The network node 111,112 being a secondary node may know such information via signaling frommaster node to the network node 111, 112 being the secondary node. Thesignaling information may include certain protocol or informationelements that indicated which core network type the network node iscommunicating with.

Action 803

This action is performed in embodiments where in embodiments where thenetwork node 111, 112 is a master node.

When the network node 111, 112 is a master node, the network node 111,112 configures the PDCP for the wireless device 120 based on which typeof core network the wireless device 120 connects to, out of the corenetwork 101 of a first type, and the core network 102 of a second type.

The configuring of the PDCP for the wireless device 120 may compriseconfiguring PDCP parameters that may be different depending on type ofnetwork, and the network node 111, 112 being a master node. These PDCPparameters may comprise any one or more out of: QoS flow ID. HeaderCompression related parameters, Encryption related parameters. Integrityprotection of user data related parameters, and parameters related toin-sequence delivery, or the size of a PDCP sequence number.

In some of these embodiments, wherein the network node 111, 112 is amaster node, the configuring the PDCP for the wireless device 120 basedon which type of core network the wireless device 120 connects to maycomprise:

-   -   When the network node 111, 112, connects to the first type of        core network, configuring the PDCP without Quality of Service.        QoS, flow Identity, ID, for the wireless device 120, and    -   when the network node 111, 112, connects to the second type of        core network configuring the PDCP with QoS flow ID for the        wireless device 120.

Action 804

This action is performed in embodiments where in embodiments where thenetwork node 111, 112 is a secondary node.

In these embodiments, when the network node 111, 112 is a secondarynode, the network node 111, 112 configures the PDCP for the wirelessdevice 120 based on any one or more out of:

-   -   (1) Which type of master node the network node 111, 112 connects        to, out of a master node of a first type, and a master node of a        second type, and    -   (2) which type of core network the wireless device 120 connects        to, out of a core network 101 of a first type, and a core        network 102 of a second type.

In these embodiments, there are two options, (1) and (2). The firstoption (1) may be used when the PDCP configuration is dependent on themaster node. This may for instance be related to what protocol releaseor radio access type the master node is. The second option (2) may beused when the PDCP configuration is dependent on the core network typethat the wireless device 120 is connected to and may for instance berelated to what QoS framework is used, or what security configuration isapplied.

The configuring of the PDCP for the wireless device 120 may compriseconfiguring PDCP parameters that may be different depending on type ofnetwork, and the network node 111, 112 being a secondary node. ThesePDCP parameters may comprise any one or more out of: QoS flow ID, HeaderCompression related parameters, Encryption related parameters. Integrityprotection of user data related parameters, and parameters related toin-sequence delivery, or the size of a PDCP sequence number.

In the embodiments, wherein the network node 111, 112 is a secondarynode, the configuring of the PDCP for the wireless device 120 based on(1) which type of master node the network node 111, 112 connects maycomprise: When the network node 111, 112, connects to the first type ofmaster node, configuring the PDCP without QoS flow ID for the wirelessdevice 120, and when the network node 111, 112, connects to the secondtype of master node, configuring the PDCP with QoS flow ID for thewireless device 120. The first type of master node may relate to an LTEnetwork node, and the second type of master node may relate to a 5G corenetwork.

In the embodiments, wherein the network node 111, 112 is a secondarynode, and the configuring of the PDCP for the wireless device 120 basedon (2) which type of core network the wireless device 120 connects tocomprises: When the wireless device 120 connects to the first type ofcore network, configuring the PDCP without QoS flow ID for the wirelessdevice 120, and when the network node 111, 112, connects to the secondtype of core network, configuring the PDCP with QoS flow ID for thewireless device 120.

Action 805

In the embodiments, wherein the network node 111, 112 is a first type ofnetwork node 111, is capable of connect to the second type of corenetwork 102, and wherein the wireless device 120 is capable to connectto the second type of core network 102, the Actions 805-807 ofconfiguration of NAS protocol below may be performed.

For the network node 111 being an eLTE eNB, it may connect to both EPCand NGCN, as it needs to support service for both 4G wireless device anda 5G wireless device. This is different from a legacy system where eachRAN node can only connect to one type of core network.

Due to this reason, if there is nothing special such as e.g. anindication of which CN is supported from the network node 111 being aneLTE eNB, the wireless device 120 cannot decide which NAS version itneed to use to connect to core network.

Therefore, the network node 111 being an eLTE eNB need to inform thewireless device 120 which core network the network node 111 connect toin its broadcast system information. Or at least if the network node 111being an eLTE eNB connects to NGCN, it needs to inform the wirelessdevice 120 that it can connect to the NGCN.

When the wireless device 120 detects such information, if the wirelessdevice 120 also supports to connect to the second type of core networksuch as NGCN, then the first NAS message transmitted by the wirelessdevice 120 toward core network will be a NAS for the second type of corenetwork such as the NGCN.

Via detect this first NAS message, the network node 111 being an eLTEeNB may then direct the wireless device 120 to the second type of corenetwork such as NGCN so that the wireless device 120 can enjoy a betterservice from the second type of core network such as NGCN.

In this action, the network node 1 may thus send to the wireless device120, information that the network node 111, 112 is capable of connect tothe second type of core network.

Action 806

In these embodiments, the network node 111 may receive from the wirelessdevice 120, a first NAS message, which NAS message is of the second typebased on the sent information.

Action 807

Based on that the NAS message is of the second type, the network node111 may then in these embodiments forwarding the NAS message of thesecond type to the second type of core network 102.

Action 808

In some embodiments the network node 111, 112 sends a command from anetwork node 111, 112 in the communications network 100, commanding thewireless device to perform the configuration performed according to theabove.

As mentioned above, the actions above may be performed in any suitableorder. E.g. regarding a user plane handling of PDCP, the wireless device120 may perform NAS signalling to the right CN before even PDCP userplane is setup. In fact PDCP configuration of user plane comes after theRAN knows which CN the wireless device 120 is attached to, e.g.according to the steps in the following example (not shown):

1. The network nodes 111, 112 in the network broadcast support for NGCNand EPC.2. The wireless device 120 selects to connect to NGCN meaning itgenerate a NAS message which is using NGCN NAS. The wireless device 120sends this message and an indication to the RAN such as the RAN 116, 117that I wants to connect to NGCN.3. Then there is some Signalling to complete the attach to NGCN.4. The RAN gets an indication from the CN that the wireless device 120is now connected to NGCN.5. The RAN configures the PDCP protocol to be used for DataTransmissions based on this information.6. The RAN sends this configuration to the wireless device 120.7. The wireless device 120 applies this configuration locally.8. Then, data can be sent.

Additionally to this above showing the configuration of PDCP for userplane, there may also a configuration of PDCP for control plane. Thismeans that the wireless device 120 may need to locally configure PDCPwhen sending the initial message to the network e.g. step 2. This issince PDCP is also used to carry RRC and NAS messages. Then there may besome other messages from RAN to further configure PDCP used for controlplane message in between step 2 and 3, e.g. RRC connection setup orre-configuration. For PDCP for a control plane message it may beunlikely that QoS flow ID will be used so in this way it may not bedifferent depending on which type of core network the wireless device120 is connecting to. However there may be some other parameters thatdiffer such as e.g. any one or more out of: Encryption relatedparameters such as PDCP sequence number used as input to encryptionalgorithm, Integrity protection of user data related parameters, orparameters related to in-sequence delivery, and the size of a PDCPsequence number.

Additionally there may be some configuration of PDCP for the wirelessdevice 120 performed for Signaling Radio Bearers (SRBs) which is used atinitial communication with the network, even prior to for the wirelessdevice 120 being attached to the core network. Also this PDCPconfiguration may be type of core network specific. This is alsoadvantageous since potentially this configuration is done for thewireless device 120 just based on the knowledge which type of corenetwork the wireless device connects to. No additional instructions maybe sent from the RAN.

Example embodiments of a method performed by the wireless device 120 forconfiguring a PDCP for the wireless device 120 in the communicationsnetwork 100 will be described with reference to a flowchart depicted inFIG. 9. As mentioned above the first type and the second type relatedifferent generations of telecommunication networks. The first type oftelecommunication network may relate to 4G. and the second type oftelecommunication network may relate to 5G.

The communications network 100 comprises the first type of core network101 and the second type of core network 102.

The method comprises the following actions, which actions may be takenin any suitable order. Actions that are optional are presented in dashedboxes in FIG. 9.

The wireless device 120 may configure its PDCP layer used fortransmission of data or signalling to the network based on the knowledgeof which type of core network the wireless device 120 connects. Theconfiguration may comprise different security configuration incl.encryption and integrity protection algorithms, or parameter setting. Itmay also include different PDCP sequence number length or other PDCPheader fields. The wireless device 120 may also select to use a specificNAS protocol depending on which CN the wireless device 120 is connectingto.

Action 901

The wireless device 120 obtains information about which type of corenetwork the wireless device connects to out of the first type and thesecond type, which first type and the second type relate to differentgenerations of telecommunication networks. This may be obtained by thewireless device 120 getting an acknowledgement from the core network thewireless device 120 has attempted to connect to or register with. Theacknowledgment could imply that the wireless device 120 should beconsidered connected to that core network.

Action 902

There may be some initial configuration of PDCP that the wireless device120 performs just based on the knowledge of which type of core networkthe wireless device 120 is connecting to or is connected to. This may bea typical example for PDCP used for signalling.

Once the wireless device 120 is connected and getting active in thenetwork to send and/or receive user plane data, the PDCP layer for userdata will be configured by the network. A RRC configuration command maybe sent to the wireless device 120 comprising instructions on how toconfigure the PDCP layer in the wireless device 120. These instructionsmay however most likely be combined with the wireless device's 120 ownknowledge about which type of core network it is connected to. Forexample, the wireless device 120 may only accept PDCP parameterconfigurations that are compatible with the type of core network towhich it is connected. As another example, the wireless device 120 mayfill in incomplete PDCP configuration information received from thenetwork, based on the type of core network involved. Here, because theRAN knows that the wireless device 120 sets one or more PDCP parametersin dependence on the type of core network it connects to, configurationinformation sent to the device from the network need not include valuesfor those parameters.

Thus, according to some embodiments herein, the wireless device 120receives a command from a network node 111, 112 in the communicationsnetwork 100, commanding the wireless device to perform theconfiguration.

The command may specify which one of the options in Action 903 below.

Action 903

According to embodiments herein, the wireless device 120 configures thePDCP for the wireless device 120 based on which type of core network thewireless device 120 connects to, out of a core network 101 of a firsttype, and a core network 102 of a second type. An advantage by basingthe configuration of the PDCP on which type of core network the wirelessdevice 120 connects to is that not all parameters of the PDCPconfiguration needs to be signaled from the network to the wirelessdevice 120 since the wireless device 120 may use the knowledge of whichcore network it is connected to in order to configure some parameters ina suitable way for that core network. Additionally the wireless device120 may detect and report erroneous configurations which are notconsistent with the core network the wireless device 120 is connectedto, avoiding possible error cases from going undetected. Additionallythe wireless device 120 may configure the initial PDCP configuration forexample used for initial signaling prior to receiving any detailedinstructions from the network based on a PDCP configuration suitable forthe core network the wireless device 120 wants to connect to or isconnected to.

The configuring of the PDCP for the wireless device 120 may compriseconfiguring PDCP parameters comprising any one or more out of: QoS flowID, Header Compression related parameters, Encryption relatedparameters. Integrity protection of user data related parameters, andparameters related to in-sequence delivery, or the size of a PDCPsequence number.

Which configuration to perform, may in some embodiments be specified inthe command.

In some embodiments, when the network node 111, 112 is a master node,the wireless device 120 configures the PDCP for the wireless device 120based on which type of core network the wireless device 120 connects to,out of the core network 101 of a first type, and the core network 102 ofa second type.

In the embodiments, wherein the network node 111, 112 is a master node,the configuring of the PDCP for the wireless device 120 based on whichtype of core network the wireless device 120 connects to comprises:

-   -   When the network node 111, 112, connects to the first type of        core network, the wireless device 120 configures the PDCP        without QoS flow ID, for the wireless device 120, and—when the        network node 111, 112, connects to the second type of core        network the wireless device 120 configures the PDCP with QoS        flow ID for the wireless device 120.

In some embodiments, when the network node 111, 112 is a secondary node,the wireless device 120 configures the PDCP for the wireless device 120based on any one or more out of:

-   -   (1) Which type of master node the network node 111, 112 connects        to, out of a master node of a first type, and a master node of a        second type, and    -   (2) which type of core network the wireless device 120 connects        to, out of a core network 101 of a first type, and a core        network 102 of a second type.

In the embodiments, wherein the network node 111, 112 is a secondarynode, the configuring of the PDCP for the wireless device 120 based on(1) which type of master node the network node 111, 112 connects maycomprise: When the network node 111, 112, connects to the first type ofmaster node, configuring the PDCP without QoS flow ID for the wirelessdevice 120, and when the network node 111, 112, connects to the secondtype of master node, configuring the PDCP with QoS flow ID for thewireless device 120. The first type of master node may relate to an LTEnetwork node, and the second type of master node may relate to a 5G corenetwork.

In the embodiments, wherein the network node 111, 112 is a secondarynode, and the configuring of the PDCP for the wireless device 120 basedon (2) which type of core network the wireless device 120 connects tomay comprise: When the wireless device 120 connects to the first type ofcore network, configuring the PDCP without QoS flow ID for the wirelessdevice 120, and when the network node 111, 112, connects to the secondtype of core network, configuring the PDCP with QoS flow ID for thewireless device 120.

The first type of telecommunication network may relate to 4G and thesecond type of telecommunication network may relate 5G. Further, thefirst type of core network may relate to an EPC core network, and thesecond type of core network may relate a 5G core network.

Action 904

In the embodiments, wherein the network node 111, 112 is a first type ofnetwork node and is capable of connect to the second type of corenetwork 102, and wherein the wireless device 120 is capable to connectto the second type of core network 102, the Action 904-905 may beperformed.

The wireless device 120 receives from the network node 111, 112information that the network node 111, 112 is capable of connect to thesecond type of core network.

Action 905

In the embodiments, the wireless device 120 may send to the network node111, 112, a first NAS message. The NAS message is of the second typebased on the sent information that the network node 111, 112 is capableof connect to the second type of core network. This enables the networknode 111, 112 to forward the NAS message is of the second type to thesecond type of core network 102.

Embodiment's herein will now be further exemplified referring to aflowchart of FIG. 10. The flowchart illustrates an example of how thenetwork node 111, 112 configures the PDCP for the wireless deviceaccording to embodiments herein.

The text below is applicable to and may be combined with any suitableembodiment described above.

The network node 111, 112 decides 1001 whether it is a master node or asecondary node for the wireless device.

The Network Node 111, 112 is a Master Node

When the network node 111, 112 is a master node, the network node 111,112 decides 1002 which out of first and second type of core network 101,102 the wireless device 120 connects to. In this example which one outof EPC and NGCN.

NGCN: When the wireless device 120 connects to the second type of corenetwork 102 in this example NGCN, the network node 111, 112 configures1003 the PDCP for the wireless device 120, referred to as UE PDCPprotocol in FIG. 10, with QoS flow ID.

EPC: When the wireless device 120 connects to the first type of corenetwork 101 in this example EPC, the network node 111, 112 configures1004 the PDCP for the wireless device 120 without QoS flow ID.

The Network Node 111, 112 is a Secondary Node

When the network node 111, 112 is a secondary node, the network node111, 112 decides 1005 which out of first and second type of master nodethe network node 111, 112 connects to. In this example which one out ofLTE eNB and NR gNB.

NR gNB: When the network node 111, 112 connects to the second type ofmaster node, in this example an NR gNB, the network node 111, 112configures 1003 the PDCP for the wireless device 120 with QoS flow ID.

LTE eNB: When the network node 111, 112 connects to the first type ofmaster node, in this example an LTE eNB, the network node 111, 112configures 1004 the PDCP for the wireless device 120 without QoS flowID.

To perform the method actions for configuring the PDCP for the wirelessdevice 120 in the communications network 100, the network node 111, 112may comprise the following arrangement depicted in FIG. 11. As mentionedabove, the communications network 100 is adapted to comprise a firsttype of core network 101 and a second type of core network 102.

The network node 111, 112 is adapted to, e.g. by means of a decidingmodule 1110 adapted to, decide whether the network node 111, 112 is amaster node or a secondary node for the wireless device 120.

The network node 111, 112 may further being adapted to e.g. by means ofthe deciding module 1110 adapted to, decide which type of core networkthe wireless device 120 connects to, out of the first type of corenetwork 101, and the second type of core network 102.

In some embodiments wherein the network node 111, 112 is a secondarynode, the network node 111, 112 may further be adapted to, e.g. by meansof the deciding module 1110 adapted to, decide which type of master nodethe network node 111, 112 connects to, out of the first type of masternode, and the second type of master node.

The network node 111, 112 is adapted to, e.g. by means of a configuringmodule 1111 adapted to:

When the network node 111, 112 is a master node, configure the PDCP forthe wireless device 120 based on which type of core network the wirelessdevice 120 connects to, out of a core network 101 of a first type, and acore network 102 of a second type, and

when the network node 111, 112 is a secondary node, configure the PDCPfor the wireless device 120 based on any one or more out of:

-   -   which type of master node the network node 111, 112 connects to,        out of a master node of a first type, and a master node of a        second type,    -   which type of core network the wireless device 120 connects to,        out of a core network 101 of a first type, and a core network        102 of a second type.

The first type and the second type are adapted to relate to differentgenerations of telecommunication networks.

The first type of telecommunication network may be adapted to relate tofourth Generation, 4G. and the second type of telecommunication networkmay be adapted to relate to a fifth Generation, 5G.

In some embodiments, wherein the network node 111, 112 is a master node,the network node 111, 112 may further be adapted to e.g. by means of theconfiguring module 1111 adapted to, configure the PDCP for the wirelessdevice 120 based on which type of core network the wireless device 120connects to by,

-   -   when the network node 111, 112, connects to the first type of        core network, configure the PDCP without Quality of Service,        QoS, flow Identity, ID, for the wireless device 120, and    -   when the network node 111, 112, connects to the second type of        core network configure the PDCP with QoS flow ID for the        wireless device 120.

The first type of core network may be adapted to relate to an EPC corenetwork, and the second type of core network may be adapted to relate toa 5G core network such as NGCN.

In some embodiments, wherein the network node 111, 112 is a secondarynode, the network node 111, 112 may further be adapted to e.g. by meansof the configuring module 1111 adapted to, configure the PDCP for thewireless device 120 based on which type of master node the network node111, 112 connects to by: When the network node 111, 112, connects to thefirst type of master node, configure the PDCP without Quality of Serviceflow Identity, ID, for the wireless device 120, and when the networknode 111, 112, connects to the second type of master node, configure thePDCP with QoS flow ID for the wireless device 120.

The first type of master node may be adapted to relate to an LTE networknode such as an eNB, and the second type of master node is adapted torelate to a 5G network node such as a 5G gNB.

In some embodiments, wherein the network node 111, 112 is a secondarynode, the network node 111, 112 may further be adapted to e.g. by meansof the configuring module 1111 adapted to, configure the PDCP for thewireless device 120 based on which type of core network the wirelessdevice 120 connects to by: When the wireless device 120 connects to thefirst type of core network, configure the PDCP without flow ID for thewireless device 120, and when the network node 111, 112, connects to thesecond type of core network, configure the PDCP with QoS flow ID for thewireless device 120.

In some embodiments, wherein the network node 111, 112 is a first typeof network node and is capable of connect to the second type of corenetwork 102, and wherein the wireless device 120 is capable to connectto the second type of core network 102, the network node 111, 112 mayfurther be adapted to, e.g. by means of a sending module 1112 adaptedto, send to the wireless device 120 information that the network node111, 112 is capable of connect to the second type of core network.

In these embodiments, the network node 111, 112 may further be adaptedto, e.g. by means of a receiving module 1113 adapted to, receive fromthe wireless device 120, a first NAS message. The NAS message is of thesecond type based on the sent information.

In these embodiments, the network node 111, 112 may further be adaptedto, e.g. by means of the sending module 1112 adapted to, based on thatthe NAS message is of the second type, forward the NAS message of thesecond type to the second type of core network 102.

In some embodiments, the network node 111, 112 may further be adapted toe.g. by means of the configuring module 1111 adapted to perform anyconfiguring of the PDCP for the wireless device 120 by any one or moreout of:

-   -   configuring for Signaling Radio Bearers. SRBs, and    -   configure the PDCP for the wireless device 120 by configuring        PDCP parameters comprising any one or more out of: QoS flow ID,        Header Compression related parameters. Encryption related        parameters, integrity protection of user data related        parameters, and parameters related to in-sequence delivery, or        the size of a PDCP sequence number.

The embodiments herein for configuring a PDCP for the wireless device120 in the communications network 100, may be implemented through one ormore processors, such as the processor 1114 of a processing circuitry inthe the network node 111, 112 depicted in FIG. 11, together withcomputer program code for performing the functions and actions of theembodiments herein. The program code mentioned above may also beprovided as a computer program product, for instance in the form of adata carrier carrying computer program code for performing theembodiments herein when being loaded into the network node 111, 112. Onesuch carrier may be in the form of a CD ROM disc. It is however feasiblewith other data carriers such as a memory stick. The computer programcode may furthermore be provided as pure program code on a server anddownloaded to the the network node 111, 112.

The network node 111, 112 may further comprise a memory 1115 comprisingone or more memory units. The memory 1115 comprises instructionsexecutable by the processor 1114.

The memory 1115 is arranged to be used to store e.g. information aboutassigned resources, data, configurations, and applications to performthe methods herein when being executed in the network node 111, 112.

In some embodiments, a computer program 1116 comprises instructions,which when executed by the at least one processor 1114, cause the atleast one processor 1114 to perform actions according to any of theActions 801-808.

In some embodiments, a carrier 1117 comprises the computer program 1116,wherein the carrier is one of an electronic signal, an optical signal,an electromagnetic signal, a magnetic signal, an electric signal, aradio signal, a microwave signal, or a computer-readable storage medium.

Those skilled in the art will also appreciate that the modules in thenetwork node 111, 112, described above may refer to a combination ofanalog and digital circuits, and/or one or more processors configuredwith software and/or firmware, e.g. stored in the memory 1115, that whenexecuted by the one or more processors such as the processor 1114 asdescribed above. One or more of these processors, as well as the otherdigital hardware, may be included in a single Application-SpecificIntegrated Circuitry (ASIC), or several processors and various digitalhardware may be distributed among several separate components, whetherindividually packaged or assembled into a system-on-a-chip (SoC).

To perform the method actions for configuring the PDCP for the wirelessdevice 120 in the communications network 100, the wireless device 120may comprise the following arrangement depicted in FIG. 12. As mentionedabove, the communications network 100 is adapted to comprise a firsttype of core network 101 and a second type of core network 102.

The wireless device 120 is adapted to, e.g. by means of an obtainingmodule 1211 adapted to obtain information about which type of corenetwork the wireless device connects to out of a first type and a secondtype adapted to relate to different generations of telecommunicationnetworks.

The wireless device 120 is further adapted to, e.g. by means of aconfiguring module 1212 adapted to configure the PDCP for the wirelessdevice 120 based on which type of core network the wireless device 120connects to, out of a core network 101 of a first type, and a corenetwork 102 of a second type.

The wireless device 120 is further adapted to, e.g. by means of areceiving module 1213 adapted to receive a command from a network node111, 112 in the communications network 100, commanding the wirelessdevice to perform the configuration.

The wireless device 120 may further be adapted to, e.g. by means of theconfiguring module 1212 adapted to, perform the configuration by:

-   -   When the network node 111, 112 is a master node, configure the        PDCP for the wireless device 120 based on which type of core        network the wireless device 120 connects to, out of a core        network 101 of a first type, and a core network 102 of a second        type, and    -   when the network node 111, 112 is a secondary node, configure        the PDCP for the wireless device 120 based on any one or more        out of:        -   which type of master node the network node 111, 112 connects            to, out of a master node of a first type, and a master node            of a second type,        -   which type of core network the wireless device 120 connects            to, out of a core network 101 of a first type, and a core            network 102 of a second type.

The first type and the second type are adapted to relate to differentgenerations of telecommunication networks.

The first type of telecommunication network may be adapted to relate to4G, and the second type of telecommunication network may be adapted torelate to 5G.

In some embodiments, wherein the network node 111, 112 is a master node,the wireless device 120 may further be adapted to, e.g. by means of theconfiguring module 1212 adapted to, configure the PDCP for the wirelessdevice 120 based on which type of core network the wireless device 120connects to by: When the network node 111, 112, connects to the firsttype of core network, configure the PDCP without Quality of Service.QoS, flow Identity, ID, for the wireless device 120, and when thenetwork node 111, 112, connects to the second type of core networkconfigure the PDCP with QoS flow ID for the wireless device 120.

The first type of core network may be adapted to relate to an EPC corenetwork, and the second type of core network may be adapted to relate toa 5G core network such as NGCN.

In some embodiments, wherein the network node 111, 112 is a secondarynode the wireless device 120 may further be adapted to, e.g. by means ofthe configuring module 1212 adapted to, configure the PDCP for thewireless device 120 based on which type of master node the network node111, 112 connects to by: When the network node 111, 112, connects to thefirst type of master node, configure the PDCP without Quality of Serviceflow Identity, ID, for the wireless device 120, and when the networknode 111, 112, connects to the second type of master node, configure thePDCP with QoS flow ID for the wireless device 120.

The first type of master node may be adapted to relate to an LTE networknode such as an eNB, and the second type of master node may be adaptedto relate to a, 5G network node such as a gNB.

In some embodiments, wherein the network node 111, 112 is a secondarynode the wireless device 120 may further be adapted to, e.g. by means ofthe configuring module 1212 adapted to, configure the PDCP for thewireless device 120 based on which type of core network the wirelessdevice 120 connects to by: When the wireless device 120 connects to thefirst type of core network, configure the PDCP without Quality ofService flow Identity, ID, for the wireless device 120, and when thenetwork node 111, 112, connects to the second type of core network,configure the PDCP with QoS flow ID for the wireless device 120.

In some embodiments, wherein the network node 111, 112 is a first typeof network node and is capable of connect to the second type of corenetwork 102, and wherein the wireless device 120 is capable to connectto the second type of core network 102, the wireless device 120 mayfurther be adapted to, e.g. by means of the receiving module 1213adapted to, receive from the network node 111, 112 information that thenetwork node 111, 112 is capable of connect to the second type of corenetwork.

In these embodiments, the wireless device 120 may further be adapted to,e.g. by means of the sending module 1214 adapted to, send to the networknode 111, 112, a first NAS message. The first NAS message is of thesecond type based on the sent information. This enables the network node111, 112 to forward the first NAS message is of the second type to thesecond type of core network 102.

In some embodiments, the wireless device 120 may further be adapted toe.g. by means of the configuring module 1212 adapted to perform theconfiguring of the PDCP for the wireless device 120 by any one or moreout of:

-   -   configuring for Signaling Radio Bearers, SRBs. and    -   configuring PDCP parameters comprising any one or more out of:        QoS flow ID, Header Compression related parameters, Encryption        related parameters, Integrity protection of user data related        parameters, and parameters related to in-sequence delivery, or        the size of a PDCP sequence number.

The embodiments herein for configuring a PDCP for the wireless device120 in the communications network 100, may be implemented through one ormore processors, such as the processor 1215 of a processing circuitry inthe the wireless device 120 depicted in FIG. 12, together with computerprogram code for performing the functions and actions of the embodimentsherein. The program code mentioned above may also be provided as acomputer program product, for instance in the form of a data carriercarrying computer program code for performing the embodiments hereinwhen being loaded into the wireless device 120. One such carrier may bein the form of a CD ROM disc. It is however feasible with other datacarriers such as a memory stick. The computer program code mayfurthermore be provided as pure program code on a server and downloadedto the the wireless device 120.

The wireless device 120 may further comprise a memory 1216 comprisingone or more memory units. The memory 1216 comprises instructionsexecutable by the processor 1215.

The memory 1216 is arranged to be used to store e.g. information aboutassigned resources, data, configurations, and applications to performthe methods herein when being executed in the wireless device 120.

In some embodiments, a computer program 1217 comprises instructions,which when executed by the at least one processor 1215, cause the atleast one processor 1215 to perform actions according to any of theActions 901-905.

In some embodiments, a carrier 1218 comprises the computer program 1217,wherein the carrier is one of an electronic signal, an optical signal,an electromagnetic signal, a magnetic signal, an electric signal, aradio signal, a microwave signal, or a computer-readable storage medium.

Those skilled in the art will also appreciate that the modules in thewireless device 120, described above may refer to a combination ofanalog and digital circuits, and/or one or more processors configuredwith software and/or firmware, e.g. stored in the memory 1216, that whenexecuted by the one or more processors such as the processor 1215 asdescribed above. One or more of these processors, as well as the otherdigital hardware, may be included in a single Application-SpecificIntegrated Circuitry (ASIC), or several processors and various digitalhardware may be distributed among several separate components, whetherindividually packaged or assembled into a system-on-a-chip (SoC).

When using the word “comprise” or “comprising” it shall be interpretedas non-limiting, i.e. meaning “consist at least of”.

The embodiments herein are not limited to the above described preferredembodiments. Various alternatives, modifications and equivalents may beused. Therefore, the above embodiments should not be taken as limitingthe scope of the invention, which is defined by the appending claims.

What is claimed is:
 1. A method of operation by a wireless device, themethod comprising: selecting a first core network of a firstcore-network type or a second core network of a second core-networktype, the first and second core networks each available through a cellof a Radio Access Network (RAN) of a RAN type supported by the wirelessdevice; and selectively configuring a Packet Data Convergence Protocol(PDCP) as a function of the selected core network, where the wirelessdevice uses the PDCP for exchanging user-plane or control-planeinformation via a radio connection with the RAN.
 2. The method of claim1, further comprising determining that the first and second corenetworks are available through the cell, based on system informationbroadcasted for the cell.
 3. The method of claim 1, wherein selectingthe first core network or the second core network comprises the wirelessdevice sending non-access stratum (NAS) signaling targeting orconfigured either for the first core network or the second core network,the NAS signaling conveyed via access stratum (AS) signaling between thewireless device and the RAN.
 4. The method of claim 1, wherein selectingthe first core network or the second core network comprises the wirelessdevice sending Radio Resource Control (RRC) signaling for the RAN,indicating one of the first and second core networks as the selectedcore network.
 5. The method of claim 1, wherein selectively configuringthe PDCP comprises determining how to set an identity of the wirelessdevice, in dependence on whether the first or the second core network isselected.
 6. The method of claim 1, wherein selectively configuring thePDCP comprises determining whether to include Quality-of-Service (QoS)flow Identities (IDs) in PDCP headers sent from the wireless device, independence on whether the first or the second core network is selected.7. The method of claim 1, wherein selectively configuring the PDCPcomprises setting one or more encryption-related parameters of the PDCP,in dependence on whether the first or the second core network isselected.
 8. The method of claim 7, wherein setting the one or moreencryption-related parameters comprises determining whether to includeone or more encryption-related header fields, in dependence on whetherthe first or the second core network is selected.
 9. The method of claim7, wherein setting the one or more encryption-related parameterscomprises determining whether to perform PDCP-layer encryption usingPDCP sequence numbers, in dependence on whether the first or the secondcore network is selected.
 10. The method of claim 1, wherein selectivelyconfiguring the PDCP comprises determining a size to use for PDCP-layersequence numbers, in dependence on whether the first or the second corenetwork is selected.
 11. A wireless device comprising: communicationcircuitry configured for wirelessly connecting to a Radio Access Network(RAN) of a RAN type supported by the wireless device; and processingcircuitry operatively associated with the communication circuitry andconfigured to: select a first core network of a first core-network typeor a second core network of a second core-network type, the first andsecond core networks each available through a cell of the RAN; andselectively configure a Packet Data Convergence Protocol (PDCP) as afunction of the selected core network, where the wireless device usesthe PDCP for exchanging user-plane or control-plane information via aradio connection with the RAN.
 12. The wireless device of claim 11,wherein the processing circuitry is configured to determine that thefirst and second core networks are available through the cell, based onsystem information broadcasted for the cell.
 13. The wireless device ofclaim 11, wherein, to select the first core network or the second corenetwork, the processing circuitry is configured to send non-accessstratum (NAS) signaling targeting or configured either for the firstcore network or the second core network, the NAS signaling conveyed viaaccess stratum (AS) signaling between the wireless device and the RAN.14. The wireless device of claim 11, wherein, to select the first corenetwork or the second core network, the processing circuitry isconfigured to send Radio Resource Control (RRC) signaling for the RAN,indicating one of the first and second core networks as the selectedcore network.
 15. The wireless device of claim 11, wherein, forselectively configuring the PDCP, the processing circuitry is configuredto determine how to set an identity of the wireless device, independence on whether the first or the second core network is selected.16. The wireless device of claim 11, wherein, for selectivelyconfiguring the PDCP, the processing circuitry is configured todetermine whether to include Quality-of-Service (QoS) flow Identities(IDs) in PDCP headers sent from the wireless device, in dependence onwhether the first or the second core network is selected.
 17. Thewireless device of claim 11, wherein, for selectively configuring thePDCP, the processing circuitry is configured to set one or moreencryption-related parameters of the PDCP, in dependence on whether thefirst or the second core network is selected.
 18. The wireless device ofclaim 17, wherein, for setting the one or more encryption-relatedparameters, the processing circuitry is configured to determine whetherto include one or more encryption-related header fields, in dependenceon whether the first or the second core network is selected.
 19. Thewireless device of claim 17, wherein, for setting the one or moreencryption-related parameters, the processing circuitry is configured todetermine whether to perform PDCP-layer encryption using PDCP sequencenumbers, in dependence on whether the first or the second core networkis selected.
 20. The wireless device of claim 11, wherein, forselectively configuring the PDCP, the processing circuitry is configuredto determine a size to use for PDCP-layer sequence numbers, independence on whether the first or the second core network is selected.